The invention is intended to be used notably with sighting binoculars intended to allow a soldier to identify a target notably by the bearing at which he sights this target through his binoculars.
In concrete terms, when he uses such binoculars, the solder has to fix and connect them to an orientation device, which is a true-north finder, and which provides these binoculars with information indicative of the orientation of north.
In practice, the north finder is incorporated into a tripod to which the binoculars are fixed in such a way that they are rigidly secured to the north finder. When the soldier is setting up his equipment he has first of all to erect the tripod and then mount the binoculars on it.
The assembly has to be placed on a fixed support so that it is immobile in relation to the ground, and arranged horizontally so that the true-north finder can operate correctly.
When the assembly is in place, the soldier triggers the process of identifying true north, for example by operating a corresponding control on the north finder.
In the identification process, the member of rate gyro type and the associated calculation means determine the projection of the earth's axis of rotation in a plane tangential to the surface of the earth, i.e. a horizontal plane, at the location being considered, the direction of this projection corresponding to the orientation of true north.
In more concrete terms, the member of rate gyro type measures the movements it experiences in order to determine the earth's axis of rotation, such that the process of determining north is ultimately relatively lengthy. Because the desired precision is of the order of one milliradian, the process of determining true north takes several minutes.
Once the operation. of determining north is over, the soldier can use his binoculars to determine the orientation of one or more targets with respect to north, the north information being transmitted to the binoculars and displayed therein.
In practice, the time taken to go through the various steps that have to be carried out in order for a soldier to be able to determine the bearing of one or more targets is long, notably bearing in mind the time it takes for the north finder to determine true north.